1. Field of the Invention
The present invention relates to a semiconductor module having a switching function for rotating a motor.
2. Description of Related Art
Motor control for a vehicle progresses further and further each year, and an electronic control unit (ECU) that is responsible for a motor and control of the motor is on the increase. On the other hand, to provide a comfortable space for a user of the vehicle, attempts are made to expand a space in a passenger compartment of the vehicle. Accordingly, it is a challenge to ensure a space for arrangement of the motor and ECU, and downsizing of the motor and ECU is becoming important.
For example, an ECU, which is used for an electric power steering system (hereinafter referred to as an EPS), is disposed behind an engine compartment or instrument panel. However, because the ECU used for the EPS drives the motor with a high current (about 100 A), heat generation of its switching element becomes great. For this reason, in order to downsize such an ECU, its structure for high heat dissipation is necessary. In this regard, a semiconductor module having a heat sink on an upper surface a semiconductor chip is proposed (see, for example, Japanese Patent No. 2685039).
Nevertheless, a semiconductor module described in the above U.S. Pat. No. 2,685,039 may not be necessarily adequate from the aspect of the heat dissipation.